Spent coffee grounds (SCG) and coffee silverskin (CS) represent a great pollution hazard if discharged into the environment. Taking this fact into account, the purpose of this study was to evaluate the chemical composition, functional properties, and structural characteristics of these agroindustrial residues in order to identify the characteristics that allow their reutilization in industrial processes. According to the results, SCG and CS are both of lignocellulosic nature. Sugars polymerized to their cellulose and hemicellulose fractions correspond to 51.5 and 40.45 % w/w, respectively; however, the hemicellulose sugars and their composition significantly differ from one residue to another. SCG and CS particles differ in terms of morphology and crystallinity, but both materials have very low porosity and similar melting point. In terms of functional properties, SCG and CS present good water and oil holding capacities, emulsion activity and stability, and antioxidant potential, being therefore great candidates for use on food and pharmaceutical fields.

The extraction of antioxidant phenolic compounds from spent coffee grounds (SCG) was studied. Extraction experiments were carried out by the conventional solid-liquid method, using methanol as solvent at different concentrations (20-100%), solvent/solid ratios (10-40 ml/g SCG), and extraction times (30-90 min), and the influence of these operational variables on the content of total phenolic compounds and antioxidant activity of the produced extracts was evaluated. Flavonoids, chlorogenic acid, and protocatechuic acid were found in all the produced extracts and were also quantified. A strong influence (p < 0.05) of the variables on the extraction results was verified, and the conditions able to maximize each response (contents of total phenolic compounds, flavonoids, chlorogenic acid and protocatechuic acid, and antioxidant activity) were established. Extraction using 60% methanol in a solvent/solid ratio of 40 ml/g SCG, during 90 min, was the most suitable condition to produce a extract with high content of phenolic compounds (16 mg gallic acid equivalents/g SCG) and high antioxidant activity (FRAP of 0.10 mM Fe(II)/g), simultaneously. These findings are of interest since antioxidant phenolic compounds have an outstanding role in health area, and wide applications in food and pharmaceutical products.

. Encapsulation of antioxidant phenolic compounds extracted from spent coffee grounds by freeze-drying and spray-drying using different coating materials. Food Chemistry, 237, 623-631. https://doi.org/10.1016Chemistry, 237, 623-631. https://doi.org/10. /j.foodchem.2017 Accepted Manuscript Encapsulation of antioxidant phenolic compounds extracted from spent coffee grounds by freeze-drying and spray-drying using different coating materials This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. achieved when PC were encapsulated by freeze-drying using maltodextrin as wall material. 35Under these conditions, the amount of PC and FLA retained in the encapsulated sample 36 corresponded to 62% and 73%, respectively, and 73-86% of the antioxidant activity present in 37 the original extract was preserved.

Spent coffee grounds (SCG), obtained during the processing of coffee powder with hot water to make soluble coffee, are the main coffee industry residues and retain approximately seventy percent of the polysaccharides present in the roasted coffee beans. The purpose of this study was to extract polysaccharides from SCG by using an alkali pretreatment with sodium hydroxide at 25°C, and determine the chemical composition, as well as the antioxidant and antimicrobial properties of the extracted polysaccharides. Galactose (60.27%mol) was the dominant sugar in the recovered polysaccharides, followed by arabinose (19.93%mol), glucose (15.37%mol) and mannose (4.43%mol). SCG polysaccharides were thermostable, and presented a typical carbohydrate pattern. Additionally, they showed good antioxidant activity through different methods and presented high antimicrobial percent inhibition against Phoma violacea and Cladosporium cladosporioides (41.27% and 54.60%, respectively). These findings allow identifying possible applications for these polysaccharides in the food industry.